Examples of Ionic Compounds

Q. NaCl forms an ionic crystal in which Cl- ions forms CCP lattice. The number of Na+ ions present at a distance of √5 A/2 from Cl- ion at the corner is

Q. 22. A compound AB crystallizes in BCC lattice with unit cell edge length of 480 pm. if radius of B(anion) is 225 pm then the radius of A(cation) is 1. 190.7 pm 2. 225 pm 3. 12.7 pm 4. 240 pm

Q. in 1 molal aqueous solution of urea, the mole fraction of urea is

Q. 16 g of SOx occupies 5.6 litres at STP. Assuming ideal gas nature, the value of x is Options:a-1 b- 2 c- 4 d-3

Q. Q . In a BCC unit cell, if half of the atoms per unit cell are removed, then percentage of vacant space is : (a) 68% (b) 32% (c) 34% (d) 66%.

Q.

In fluorite structure (CaF₂)

1. Ca²⁺ ions are ccp and F^- ions are present in all the tetrahedral voids

2. Ca²⁺ ions are ccp and F^- ions are present in all the octahedral voids

3. Ca²⁺ ions are ccp and F^- ions are present in all the octahedral voids & half of thetetrahedral voids

4. None

Q. 1. How many unit cells are present in 5.0 gram of crystal AB ( formula mass of AB=40) having rock salt type?

Q. In fluorite structure :-

1. $C{a}^{+2}$ ions are ccp and $F^{-}$ ions are in octahedral voids
   
2. $C{a}^{+2}$ ions are ccp and $F^{-}$ ions are in tetrahedral voids
   
3. $C{a}^{+2}$ ions are in bcc and $F^{-}$ ions are in cubical voids
   
4. $F^{-}$ ions are ccp and $C{a}^{+2}$ ions are in tetrahedral voids

Q.
A mineral has the formula $A{B}_2$ and crystallizes in the cubic close packed lattice, with atoms A occupying the lattice points. The co-ordination number and the fraction of tetrahedral sites occupied by atoms B are:

1. 4, 100%
2. 6, 75%
3. 1, 25%
4. 6, 50%

Q.

Which of the following statements is not true about NaCl structure

[DCE 2001]

1. Cl^- ions are in fcc arrangement

2. Na⁺ ions has coordination number 4

3. Cl^- ions has coordination number 6

4. Each unit cell contains 4 NaCl molecules

Q. Is trigonal and rhombohedral the same? What is bravias lattice for triclinic?

Q. If Zn2+ ions lying on one of the body diagonals ofZnS (sphalerite) unit cell are removed, the ratio ofcation and anion would become (1) 4:3 (2) 3:4 (4) 8:7(3) 7:8

Q. 77 The second coordination number of cl- in the Nacl unit is?? Explain how to find 2nd. C.N.

Q. In a solid, oxide ions are arranged in ccp. One-sixth of tetrahedral voids are occupied by cation A while one-third of octahedral voids are occupied by cation B. What is the formula of compound?

1. $A{B}_{2}O$
2. $A_2{B}_{3}O$
3. $AB{O}_3$
4. $A_3{B}_{2}O$

Q. The distance between an octahedral and tetrahedral void in fcc lattice?

Q. 33 How number of oxide ions per unit cell is 4?

Q. 10 A certain sample of Cuprous sulphide is found to have composition Cu1.8S , because of incorporation of Cu+2 ions in the lattice. What is the mole % of Cu+2 in total copper content in the crystal?

Q. In the Lewis dot structure of SO2 explain how sulphur becomes stable.

Q. 21. Which of the following has highest number offormula units per unit cell?(1) NaCI type structure(2) Na2O type structure(3) CaF2 type structure(4) All have same number of formula unit

Q. 47.Why is NH3 a base when it lacks OH ions?

Q. What is the minimum distance between two $N{a}^{+}$ ions which are present along the edges in an ideal NaCl type crystal? Let, $r_{N{a}^{+}}$= radius of Na ⁺ and $r_{C{l}^{-}}$= radius of $C{l}^{-}$.

1. 
   $2\left(r_{N{a}^{+}}\right)$
2. $2\times (\sqrt{2}+1)r_{N{a}^{+}}$
3. $2r_{C{l}^{-}}$
4. $\sqrt{2}\times (r_{N{a}^{+}}+r_{C{l}^{-}})$

Q. 31. In normal spinel structure there is a closed pack of array O2- ions.the trivalent cations are present in?

Q. How many atoms are there in end - centred cubic unit cell

Q.

In which of the following crystals alternate tetrahedral voids are occupied?

1. $NaCl$

2. $ZnS$

3. $Ca{F}_2$

4. $N{a}_{2}O$

Q. What is the minimum distance between two $N{a}^{+}$ ions which are present along the edges in an ideal NaCl type crystal? Let, $r_{N{a}^{+}}$= radius of Na ⁺ and $r_{C{l}^{-}}$= radius of $C{l}^{-}$.

1. 
   $2\left(r_{N{a}^{+}}\right)$
2. $2\times (\sqrt{2}+1)r_{N{a}^{+}}$
3. $2r_{C{l}^{-}}$
4. $\sqrt{2}\times (r_{N{a}^{+}}+r_{C{l}^{-}})$

Q.

Which of the following are TRUE for $ZnS$ type and $Ca{F}_2$ type structure?

1. $ZnS$ – 6:6 coordination; $Ca{F}_2$ – 8:4 coordination

2. $ZnS$ – 4:4 coordination; $Ca{F}_2$ – 8:4 coordination

3. $ZnS$ – $Z{n}^{2+}$ at half of tetrahedral voids; $Ca{F}_2$ – F^- ions are at all tetrahedral voids

4. $ZnS$ – $Z{n}^{2+}$ at all of tetrahedral voids; $Ca{F}_2$ – F^- ions are at all tetrahedral voids

Q. In which of the following crystals, alternate tetrahedral voids are occupied?

1. NaCl
2. ZnS
3. $Ca{F}_2$
4. $N{a}_{2}O$

Q.

CsCl has ______ Coordination.

1. 6:6

2. 8: 8

3. 4:8

4. 8:4

Q. 82. in a unit cell a B C and D are present at corners Face centres body centres and edge centre if atoms touching one of the plane passing through two diagonal opposite edges are removed then formula of compound is

Q. By dissolving $13.6g$ of a substance in $20g$ of water, the freezing point decreased by ${3.7}^{\circ }C$. Calculate the molecular mass of the substance. (Molal depression constant for water = $1.863Kkgmo{l}^{-1}$)

1. $242.4g/mol$
2. $432.4g/mol$
3. $342.4g/mol$
4. $243.4g/mol$